GB2108773A

GB2108773A - A tool for removing insulation from cables

Info

Publication number: GB2108773A
Application number: GB08130869A
Authority: GB
Inventors: Hans Undin; Hans Wiener
Original assignee: Weidmueller GmbH and Co KG
Current assignee: Weidmueller GmbH and Co KG
Priority date: 1980-08-29
Filing date: 1981-10-13
Publication date: 1983-05-18
Also published as: SE8006042L; FR2514960B1; FR2514960A1; US4472877A; SE460939B; DE3140193A1; GB2108773B

Abstract

The tool has a housing (18) for a blade (5), the housing being rotatably mounted in a body (17) of the tool and having a supporting surface (23) for the cable to be stripped of insulation, the surface having a central recess (23a) which provides better support for the cable. A holder stirrup (2) presses the cable on to the blade (5), and has a tapered, end portion (2a) serving for breaking off a cut portion of insulation. The tool is particularly suitable for removing insulation from cables of large diameter, e.g. diameter between 6 and 30 mm. The tool is first used to make a peripheral cut through the insulation (Fig. 7 not shown) and then the blade (5) rotated vertically through 90 DEG by a handle (4) to make a longitudinal cut (Fig. 8 not shown). A spare blade may be stored (16c) in the bottom of the tool (Fig. 2 not shown). <IMAGE>

Description

1

SPECIFICATION

A tool for removing insulation from cables The invention relates to a tool for removing ' insulation from cables, the tool being of the type in which the cable end to be stripped of insulation is surrounded by a holder stirrup and first to a stripping blade is pierced at a single place into the insulation whereafter the whole tool is turned by means of a pin-shaped handle around the cable whereby the hole caused by piercing is extended around the whole periphery of the cable. The knife can then be rotated about its axis through 901 and by axial displacement of the tool about the severed part of insulation this part is slit for easy removal. Tools of this kind are shown e.g. from British Patent Specification No. 1458366.

The aim of the invention is to further improve such tool, particularly as regards convenient handling and reliable function when stripping insulation from cables of large diameter.

The invention provides a tool for removing insulation from cables, particularly cables of large diameter, comprising a cutting blade situated in a housing the housing having a supporting surface for the cable to be stripped and being rotatably mounted in an elongate body of the tool, the tool further comprising a holder stirrup for pressing the cable onto the blade, wherein said supporting surface has a central recess for receiving a portion of the cable insulation.

The invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:- Figure 1 is a side elevation of a tool according to the invention, Figure 2 shows the tool according to Figure 2 from below on a larger scale, Figure 3 is an axial section, also on a larger scale, through the upper part of the tool according to Fig. 1, Figure 4 is a side view of a preferred embodiment of a blade, also on a larger scale, Figure 5 is a section along line V-V in Fig. 4, Figure 6 is a plan of the end part of the holder 45. stirrup according to Figure 1, - Figure 7 is aside elevation, on a smaller scale, of a known embodiment of a supporting area, and Figures 8 and 9 show, on a larger scale, the function of the tool having a supporting area according to the invention.

Figures 1 to 3 show a replaceable cutting blade 5 situated in a housing 18. The housing 18 is provided with a lever 4 and is rotatably mounted in an elongate body 17 of the tool which has the form of a handle.The lever4 moves in a slit3 in the body 17 which is so dimensioned that the turning movement of the housing 18 takes place within desired limits.

Due to the lever 4 being guided in the slit 3, also the housing 18 is firmly held in the body 17. The blade 5 has at its end remote from the cutting end, a planar portion or tongue 13 (Fig.4) which fits into a coresponding recess 19 (Fig.3) in the housing 18. Due to this the exchangeable blade 5 GB 2 108 773 A 1 is non-rotatably connected to the rotatable housing 18. The depth T of cutting of the blade 5 is adjustable by a knurled adjustment screw 7 screwed into the housing 18. A compression spring 10 (Fig.3) which increases the frictional resistance in the screw connection, ensures that the adjustment remains unchanged even when the housing 18 is turned. The spring 10 inhibits undesired turning of the adjustment screw.

The housing 18 is in one of its end positions, defined by the slit 3, held by a torsionally stressed spring 11 which at one of its ends 11 a engages with an ear (not shown) in an axial recess 12 in the housing 18 and at its other end 11 b in a recess (not shown) in the body 17. The spring 11 inhibits undesired turning of the housing.

The roof-shaped holder stirrup has a guide portion 2b inserted in the body 17 and constantly pulled by a tension spring 15, one end of which is connected to the portion 2b, into the housing 18. The other end of the tension spring 15 is anchored by a transversely extending retaining pin 14 (Fig.2) for which two elongate receiving grooves 1 6a, 1 6b, extending at an angle to each other, are provided in the bottom 1 7a of the body 17. From the groove 1 6b extends axially a bore 1 6c which forms a storage space for at least one spare blade 5'. Figure 2 shows how this bore 16c is made accessible by displacing the transverse pin 14 in the direction indicated by the arrow P from the groove 1 6b into the groove 16a. After removal of the spare blade (or after insertion of a new spare blade) the transverse pin 14 is again transferred into the groove 1 6b and serves as a cover for the storagespace.

The free end 2a of the holder stirrup 2 is gradually reduced in thickness, though not in width, as is apparent from Figures 1 and 6; consequently it does not end in a point. The end 2a reduced in thickness may be used, if needed, for breaking up the severed part of insulation.

In known tools for removing insulation of the described type the supporting surface 22 surrounding the blade is in the form of a spherical cap, as is shown in Figure 7, which results in rolling off of the cable 30 the insulation of which is to be removed. According to the invention the supporting surface 23 has a central recess 23a, and the housing 18 is preferably so made that it converges to the periphery of the recess 23a, e.g. is provided with a bevelled edge 23b (Fig.8) or has outside the recess 23a the known shape in the form of a spherical cap according to Fig.7.

The recess 23a is in the illustrated example arranged on the said adjustment screw 7. The blade 5 is so locked in the housing 18 that it cannot turn or change its height, because its tongue 13 is received in the recess 19. In the adjustment screw 7 is an axial cylindrical opening 7a and the central part 5c of the cutting blade 5 is of circular crosssection, so that it is reliably guided in all rotational positions of the adjustment screw 7. The dimensions of the cylindrical part 5c of the blade 5 and of the cylindrical opening 7a fit 2 GB 2 108 773 A 2 accurately one into the other.

The new supporting surface 23 forms a better boundry limit for the cable 30 held by the holder stirrup 2 and prevents if from rolling off. In addition a tool according to the invention has the following advantages:

When the cutting blade penetrates into the insulation layer 34a of the cable 30 (Fig.9) a bulge 30al is formed by that layer for which there is space in the recess 23a so that there is no increased friction, as is the case with the known tool, between the cable and the holder stirrup.

When the severed part of insulation is axially cut through, the cable can be near its end positioned somewhat obliquely, as is apparent from Figure 8. This ensures cutting through the insulation up to its end.

Because the size of the said bulge 30a'formed by the insulation 30a depends on the volume of the cutting blade penetrating into the insulation, it is further advantageous to keep the blade 5 according to Figure 5 as narrow as possible and preferably provide it with two cutting edges 5a and 5b. In that case the blade 5 dislodges a smaller amount of the insulation material and its resistance on cutting of the insulation layer is smaller.

Because the blade 5 has two cutting edges 5a, 5b, the tool may be turned about the cable 30 in both senses, and for this purpose the slit 3 is made 85 so wide that it enables the housing 18 to be turned, the body 17 through 1800. In addition this increases the life of the blade 5 because when one of the cutting edges becomes blunt the other may be positioned to cut in the preferred direction 90 of cutting.

While a tool according to the invention is particularly suitable for removing insulation from cables of a relatively large diameter, for instance 6 to 30mm, the tool is suitable in principle also for 95 the stripping of insulation from other cables.

Claims

1. A tool for removing insulation from cables, particularly cables of large diameter, comprising a 100 cutting blade situated in a housing, the housing having a supporting surface for the cable to be stripped and being rotatably mounted on an elongate body of the tool, the tool further comprising a holder stirrup for pressing the cable on to the blade, wherein said supporting surface has a central recess for receiving a portion of the cable insulation.

2. A tool according to Claim 1 wherein the blade has two cutting edges each extending along 110 one of two opposite longitudinal edges of the blade.

3. A too[ according to Claim 1 or 2 wherein the housing is rotatable relative to the body of the tool through 1801. 60

4. A tool according to any one of the preceding claims including an element inhibiting rotation of the housing.

5. A tool according to any one of the preceding claims wherein the holder stirrup has a substantially roof-shaped part which has a free end delimited by two opposite converging sides such that its thickness is reduced while its width remains unchanged.

6. A tool according to any one of the preceding claims wherein the cross-seCtion of the housing decreases towards the central recess.

7. A tool according to any one of the preceding claims wherein a storage space is formed in the body for at least one replacement blade, the space extending to the bottom of the body, wherein the holder stirrup has an elongate rectilinear part extending, and biased by a spring, into the body of the tool, and wherein said spring is at its bottom end anchored by a transverse pin which closes the entry into the storage room in such a way that the replacement blade may be removed therefrom on overcoming the force exerted by said spring.

8. A tool according to any one of the preceding claims, wherein the central recess is provided in an adjustment screw which may be screwed to a desired degree into the hcusing, while the blade has along a part of its length a circular cross section which extends through a cylindrical axial opehing in the adjustment screw and is non rotatably and axially non-displaceably anchored in the housing so that the depth of penetration of the cutting blade above the recess in the supporting surface may be determined by the adjustment of the adjustment screw.

9. A tool according to Claim 8 including a rotation inhibiting element acting on the adjustment screw.

10. A tool for removing insulation from a cable, constructed, arranged and adapted to operate substantially as herein described with reference to, and as shown in Figures 1 to 6, 8 and 9 of the accompanying drawings.

11. A cable the insulation of which was removed by a too[ according to any one of the 7 preceding claims.

12. A method of removing insulation from a cable substantially as herein described with reference to Figures 1 to 6, 8 and 9 of the accompanying drawings.

13. A cable the insulation of which was removed by a method according to Claim 12.

Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1983. Published by the Patent'Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained.

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